how to decrypt AES-ECB-Nopadding data?

[Milan]

Hi Team,

Can anyone help me on this?

How to decrypt AES-ECB-Nopadding Encrypted frame?

I am not getting desired output. In fact, I am not getting how to proceed in this case.

[endnode]

Oh, it was definitely not clear that you are asking about decryption of packets captured by Nordic BLE Sniffer in Wireshark. Just quickly looking into "nRF_Sniffer_User_Guide_v1.1.pdf" and there is pretty clear how you should proceed in all 3 cases ("Just Works", "Passkey" or "OOB" mode). Am I missing something? Or are you using some applicative AES encryption and you wish to have it decrypted on the fly in Wireshark?

Cheers Jan

[Dave_couling]

I second this question

[endnode]

Hi both, I've thought it's crystal clear in provided link but in case it's not: NO, there is no AES decryption function in Nordic SDK (because there is no HW acceleration for it on nRF51 chip). The SDK documentation is confusing when mentioning word "decrypt" but if you go deeper you see that there is actually no way how call this decrypt functionality.

Cheers Jan

[Dave_couling]

So if I call nrf_ecb_crypt ( uint8_t * dst, const uint8_t * src ) with cleantext it will encrypt.

If I call this function again with the same Key and using the encrypted data, it should return the original cleantext data no?

[endnode]

Hi Dave, hitting limit for simple comment so I'm amending my answer above. Please read it. Cheers Jan